I managed to reset my iPad2 by simultaneously pressing two keys (Sleep/Wake & Home) for 10 seconds or more. See the Appendix in the iPad User Manual). Then I entered the correct AppleID and password into the iCloud Settings.
You must use a computer. There is no way around it for you.
You have to restore the device within iTunes. You can restore with any other computer, but you will lose everything on the iPad. You will have to download all of your purchased content again after you unlock the device.